Iftikhar Aziz / mbed-dev

4545

Dependents:   LSS_Rev_1

Fork of mbed-dev by Umar Naeem

targets/TARGET_STM/trng_api.c@166:33361e55dd8c, 2017-08-23 (annotated)

Committer:
iftaziz
Date:
Wed Aug 23 10:32:38 2017 +0000
Revision:
166:33361e55dd8c
Parent:
149:156823d33999 
r1

Who changed what in which revision?

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<> 149:156823d33999 1 /*
<> 149:156823d33999 2 * Hardware entropy collector for the STM32 families
<> 149:156823d33999 3 *
<> 149:156823d33999 4 * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
<> 149:156823d33999 5 * SPDX-License-Identifier: Apache-2.0
<> 149:156823d33999 6 *
<> 149:156823d33999 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
<> 149:156823d33999 8 * not use this file except in compliance with the License.
<> 149:156823d33999 9 * You may obtain a copy of the License at
<> 149:156823d33999 10 *
<> 149:156823d33999 11 * http://www.apache.org/licenses/LICENSE-2.0
<> 149:156823d33999 12 *
<> 149:156823d33999 13 * Unless required by applicable law or agreed to in writing, software
<> 149:156823d33999 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
<> 149:156823d33999 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 149:156823d33999 16 * See the License for the specific language governing permissions and
<> 149:156823d33999 17 * limitations under the License.
<> 149:156823d33999 18 *
<> 149:156823d33999 19 */
<> 149:156823d33999 20
<> 149:156823d33999 21 #if defined(DEVICE_TRNG)
<> 149:156823d33999 22
<> 149:156823d33999 23 #include <stdlib.h>
<> 149:156823d33999 24 #include "cmsis.h"
<> 149:156823d33999 25 #include "trng_api.h"
<> 149:156823d33999 26
<> 149:156823d33999 27 /** trng_get_byte
<> 149:156823d33999 28 * @brief Get one byte of entropy from the RNG, assuming it is up and running.
<> 149:156823d33999 29 * @param obj TRNG obj
<> 149:156823d33999 30 * @param pointer to the hardware generated random byte.
<> 149:156823d33999 31 */
<> 149:156823d33999 32 static void trng_get_byte(trng_t *obj, unsigned char *byte )
<> 149:156823d33999 33 {
<> 149:156823d33999 34 *byte = (unsigned char)HAL_RNG_GetRandomNumber(&obj->handle);
<> 149:156823d33999 35 }
<> 149:156823d33999 36
<> 149:156823d33999 37 void trng_init(trng_t *obj)
<> 149:156823d33999 38 {
<> 149:156823d33999 39 #if defined(TARGET_STM32L4)
<> 149:156823d33999 40 RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
<> 149:156823d33999 41
<> 149:156823d33999 42 /*Select PLLQ output as RNG clock source */
<> 149:156823d33999 43 PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RNG;
<> 149:156823d33999 44 PeriphClkInitStruct.RngClockSelection = RCC_RNGCLKSOURCE_PLL;
<> 149:156823d33999 45 HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
<> 149:156823d33999 46 #endif
<> 149:156823d33999 47
<> 149:156823d33999 48 /* RNG Peripheral clock enable */
<> 149:156823d33999 49 __HAL_RCC_RNG_CLK_ENABLE();
<> 149:156823d33999 50
<> 149:156823d33999 51 /* Initialize RNG instance */
<> 149:156823d33999 52 obj->handle.Instance = RNG;
<> 149:156823d33999 53 HAL_RNG_Init(&obj->handle);
<> 149:156823d33999 54
<> 149:156823d33999 55 /* first random number generated after setting the RNGEN bit should not be used */
<> 149:156823d33999 56 HAL_RNG_GetRandomNumber(&obj->handle);
<> 149:156823d33999 57
<> 149:156823d33999 58 }
<> 149:156823d33999 59
<> 149:156823d33999 60 void trng_free(trng_t *obj)
<> 149:156823d33999 61 {
<> 149:156823d33999 62 /*Disable the RNG peripheral */
<> 149:156823d33999 63 HAL_RNG_DeInit(&obj->handle);
<> 149:156823d33999 64 /* RNG Peripheral clock disable - assume we're the only users of RNG */
<> 149:156823d33999 65 __HAL_RCC_RNG_CLK_DISABLE();
<> 149:156823d33999 66 }
<> 149:156823d33999 67
<> 149:156823d33999 68 int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
<> 149:156823d33999 69 {
<> 149:156823d33999 70 int ret;
<> 149:156823d33999 71
<> 149:156823d33999 72 /* Get Random byte */
<> 149:156823d33999 73 for( uint32_t i = 0; i < length; i++ ){
<> 149:156823d33999 74 trng_get_byte(obj, output + i );
<> 149:156823d33999 75 }
<> 149:156823d33999 76
<> 149:156823d33999 77 *output_length = length;
<> 149:156823d33999 78 /* Just be extra sure that we didn't do it wrong */
<> 149:156823d33999 79 if( ( __HAL_RNG_GET_FLAG(&obj->handle, (RNG_FLAG_CECS | RNG_FLAG_SECS)) ) != 0 ) {
<> 149:156823d33999 80 ret = -1;
<> 149:156823d33999 81 } else {
<> 149:156823d33999 82 ret = 0;
<> 149:156823d33999 83 }
<> 149:156823d33999 84
<> 149:156823d33999 85 return( ret );
<> 149:156823d33999 86 }
<> 149:156823d33999 87
<> 149:156823d33999 88 #endif